Crush lesions were made on sciatic nerves of rats. We examined the influence on recovery of the time elapsed between successive injuries and of location and number of damaged sites. The results were assessed over a post-operative period of 2.5 months by studying tracks obtained from walking rats. This study demonstrated the central role of basal lamina tube lesions in nerve injuries. In contrast, neither injury to the tissue of the nerve (Schwann cells), nor to the neurite itself influenced the functional outcome.